Year	%
1971	99.16539
1972	99.1243
1973	98.9915
1974	99.16519
1975	99.43063
1976	99.55351
1977	99.63771
1978	99.75716
1979	99.44631
1980	99.85332
1981	99.83169
1982	99.89097
1983	99.73831
1984	99.79287
1985	99.69746
1986	99.78252
1987	99.5426
1988	99.87266
1989	99.76211
1990	100
1991	99.96292
1992	100
1996	99.4268
1997	99.40123
1998	99.24903
1999	99.36692
2000	99.99236
2001	99.46997
2002	99.86648
2003	99.8428
2004	99.65753
2005	99.61424
2006	99.62193
2007	99.84458
2008	99.65788
2009	99.82177
2010	99.68042
2012	99.32605
2013	99.61025
2014	99.64058
2015	99.84498
2016	99.50456